Mockito+PowerMock+Junit单元测试

一、单元测试用途

1、日常开发团队要求规范，需要对开发需求代码进行单元测试并要求行覆盖率达到要求，DevOps流水线也会开设相关门禁阀值阻断代码提交，一般新增代码行覆盖率80%左右。

二、Mock测试介绍

1、Mock是为了解决不同的单元之间由于耦合而难于开发、测试的问题。所以，Mock既能出现在单元测试中，也会出现在集成测试、系统测试过程中。Mock 最大的功能是帮你把单元测试的耦合分解开，如果你的代码对另一个类或者接口有依赖，它能够帮你模拟这些依赖，并帮你验证所调用的依赖的行为。

2、Mock 测试就是在测试活动中，对于某些不容易构造或者不容易获取的比较复杂的数据/场景，用一个虚拟的对象(Mock对象)来创建用于测试的测试方法。

3、Mock重要作用

Mock是为了解决不同的单元之间由于耦合而难于开发、测试的问题。所以，Mock既能出现在单元测试中，也会出现在集成测试、系统测试过程中。

Mock 最大的功能是帮你把单元测试的耦合分解开，如果你的代码对另一个类或者接口有依赖，它能够帮你模拟这些依赖，并帮你验证所调用的依赖的行为。

三、Mock测试所需依赖

1、主要引入mockito-core/powermock-core

        <dependency><groupId>org.mockito</groupId><artifactId>mockito-core</artifactId><version>4.5.1</version><scope>test</scope></dependency><dependency><groupId>org.powermock</groupId><artifactId>powermock-core</artifactId><version>2.0.9</version></dependency><dependency><groupId>org.powermock</groupId><artifactId>powermock-module-junit4</artifactId><version>2.0.9</version></dependency><dependency><groupId>org.powermock</groupId><artifactId>powermock-api-mockito2</artifactId><version>2.0.9</version><scope>test</scope></dependency>

Mockito和PowerMock都是单元测试模拟框架，用于模拟被测试类的依赖项。Mockito基于动态代理的方式实现，而PowerMock在Mockito基础上增加了类加载器以及字节码篡改技术，使其可以实现对private/static/final方法的Mock

四、Mock的核心功能

1、Mock对象创建

Mockito.mock(List.class); // Mock对象创建

public class VerifyMockExample {@Testpublic void testVerifyMock() {List<String> mockList = Mockito.mock(List.class);// 调用Mock对象的方法mockList.add("testCode");mockList.size();// 验证mockList.add("test")是否被调用过一次Mockito.verify(mockList,Mockito.times(1)).add("testCode");// 验证size()方法是否被调用过Mockito.verify(mockList,Mockito.times(1)).size();Assert.assertFalse(mockList.size()==1);}
}

verify系列方法

Mockito.verify/Mockito.times()验证调用次数

·verify(mock).methodCall()：验证方法被调用

· verify(mock, times(n)).methodCall()：验证方法被调用n次

· verify(mock, never()).methodCall()：验证方法从未被调用

或者是通过注解来实现创建

    @Mockprivate UserInfoMapper mockUserInfoMapper;@InjectMocksprivate UserInfoServiceImpl userInfoServiceImplUnderTest;

    @Testpublic void testVerifyMock2(){List<String> mockList = Mockito.mock(List.class);mockList.add("Code1");mockList.add("Code2");// 验证是否调用两次Mockito.verify(mockList,Mockito.times(2));}

 // 验证这个方法从没有被调用过Mockito.verify(userMapper, Mockito.never()).getUserById(1);userMapper.getUserById(1);// 验证这个方法至少调用了1次Mockito.verify(userMapper, Mockito.atLeastOnce()).getUserById(1);userMapper.getUserById(1);// 验证当前方法调用了2次Mockito.verify(userMapper, Mockito.times(2)).getUserById(1);

Mockito.when()使用when和thenReturn方法配置Mock对象的行为

Mockito.when( 对象.方法名 ).thenReturn( 自定义结果) //当调用了某个 Mock 对象的方法时，就回传我们想要的自定义结果。

thenReturn系列方法

//当使用任何整数值调用 userService 的 getUserById 方法时，就回传一个名字为 I'm mock 3 的 User 对象。
Mockito.when(userService.getUserById(Mockito.anyInt)).thenReturn( newUser( 3, "I'm mock"));
//限制只有当参数的数字是 3 时，才会回传名字为 I'm mock 3 的 user 对象。
Mockito.when(userService.getUserById( 3)).thenReturn( newUser( 3, "I'm mock"));
//当调用 userService 的 insertUser 方法时，不管传进来的 user 是什么，都回传 100。
Mockito.when(userService.insertUser(Mockito.any(User.class))).thenReturn( 100);

thenThrow系列方法

//当调用 userService 的 getUserById 时的参数是 8 时，抛出一个 RuntimeException。
Mockito.when(userService.getUserById( 8)).thenThrow( new RuntimeException( "mock throw exception"));
//如果方法没有返回值的话（即方法定义为 public void myMethod {...}），要改用 doThrow 抛出 Exception。
Mockito.doThrow( new RuntimeException( "mock throw exception")).when(userService.print);

    @Testpublic void testVerifyMock3(){List<String> mockList = Mockito.mock(List.class);// 设置Mock对象的预期行为Mockito.when(mockList.get(0)).thenReturn("mockedValue");// 断言验证返回值Assert.assertEquals("mockedValue",mockList.get(0));}

实战案例：测试一个UserInfoServiceImpl层saveUser()方法.

原始方法：

    @Transactional@Overridepublic void saveUser(UserInfo userInfo){userInfoMapper.saveUser(userInfo);}

单元测试：

    @Testpublic void testSaveUser() {// Setupfinal UserInfo userInfo = new UserInfo();userInfo.setId(0);userInfo.setUserName("userName");userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());// Run the testuserInfoServiceImplUnderTest.saveUser(userInfo);// Verify the resultsMockito.verify(mockUserInfoMapper).saveUser(new UserInfo());}

原始方法：

    @Overridepublic List<UserInfo> queryListByUserName(String userName) {return userInfoMapper.queryListByUserName(userName);}

单元测试方法：

    @Testpublic void testQueryListByUserName() {// Setupfinal UserInfo userInfo = new UserInfo();userInfo.setId(0);userInfo.setUserName("userName");userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());final List<UserInfo> expectedResult = Arrays.asList(userInfo);// Configure UserInfoMapper.queryListByUserName(...).final UserInfo userInfo1 = new UserInfo();userInfo1.setId(0);userInfo1.setUserName("userName");userInfo1.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo1.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());final List<UserInfo> userInfos = Arrays.asList(userInfo1);when(mockUserInfoMapper.queryListByUserName("userName")).thenReturn(userInfos);// Run the testfinal List<UserInfo> result = userInfoServiceImplUnderTest.queryListByUserName("userName");// Verify the resultsassertThat(result).isEqualTo(expectedResult);}@Testpublic void testQueryListByUserName_UserInfoMapperReturnsNoItems() {// Setupwhen(mockUserInfoMapper.queryListByUserName("userName")).thenReturn(Collections.emptyList());// Run the testfinal List<UserInfo> result = userInfoServiceImplUnderTest.queryListByUserName("userName");// Verify the resultsassertThat(result).isEqualTo(Collections.emptyList());}

原始方法：

    @Overridepublic List<UserInfo> queryUserInfoList(String createTime, List<Integer> idList) {return userInfoMapper.queryListByIds(createTime,idList);}

单元测试方法：

    @Testpublic void testQueryUserInfoList() {// Setupfinal UserInfo userInfo = new UserInfo();userInfo.setId(0);userInfo.setUserName("userName");userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());final List<UserInfo> expectedResult = Arrays.asList(userInfo);// Configure UserInfoMapper.queryListByIds(...).final UserInfo userInfo1 = new UserInfo();userInfo1.setId(0);userInfo1.setUserName("userName");userInfo1.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo1.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());final List<UserInfo> userInfos = Arrays.asList(userInfo1);when(mockUserInfoMapper.queryListByIds("createTime", Arrays.asList(0))).thenReturn(userInfos);// Run the testfinal List<UserInfo> result = userInfoServiceImplUnderTest.queryUserInfoList("createTime", Arrays.asList(0));// Verify the resultsassertThat(result).isEqualTo(expectedResult);}@Testpublic void testQueryUserInfoList_UserInfoMapperReturnsNoItems() {// Setupwhen(mockUserInfoMapper.queryListByIds("createTime", Arrays.asList(0))).thenReturn(Collections.emptyList());// Run the testfinal List<UserInfo> result = userInfoServiceImplUnderTest.queryUserInfoList("createTime", Arrays.asList(0));// Verify the resultsassertThat(result).isEqualTo(Collections.emptyList());}

原始方法：Controller层，MockMvc

mockMvc.perform(request)：执行一个HTTP请求，并返回ResultActions对象。
ResultActions.andExpect(expected)：验证请求的处理结果，如状态码、响应体等。
ResultActions.andDo(handler)：处理请求的响应，如将响应体写入文件等。
ResultActions.andReturn()：返回已执行请求的结果，以便直接访问结果。
MockMvc.perform(request).andExpect(expected).andDo(handler).andReturn()：链式调用，执行请求、验证结果并处理响应，返回结果。


@Slf4j
@RestController
public class UserInfoController {@Autowiredprivate UserInfoService userInfoService;/*** 查询全部列表* @return*/@RequestMapping("/boot/query/users")public List<UserInfo> getUserInfoList(){List<UserInfo> list = userInfoService.list();return list;}/*** 保存用户信息* @return*/@RequestMapping("/boot/save/user")public String saveUser(){try {UserInfo user=new UserInfo();user.setUserName("MyBatis Log Free");userInfoService.save(user);} catch (Exception e) {log.error("save user error", e);throw new GlobalException("save user error");}return "success";}@RequestMapping("/boot/query/users/ids")public List<UserInfo> getUserInfoListIds(){List<Integer> list = Arrays.asList(1, 3, 5);String createTime="2022-09-05 15:11:21";List<UserInfo> userInfos = userInfoService.queryUserInfoList(createTime,list);return userInfos;}@RequestMapping("/boot/query/users/like")public List<UserInfo> getUserInfoListLike(){List<UserInfo> infoList = userInfoService.queryListByUserName("A");return infoList;}@RequestMapping("/boot/save/userinfo")public void saveUserInfo(){UserInfo userInfo = new UserInfo();userInfo.setId(5);userInfo.setUserName("Puck");Date startTime = new Date();Date endTime = new Date();userInfo.setCreateTime(startTime);userInfo.setUpdateTime(endTime);userInfoService.saveUser(userInfo);}
}

单元测试方法如下:

@RunWith(SpringRunner.class)
@WebMvcTest(UserInfoController.class)
public class UserInfoControllerTest {@Autowiredprivate MockMvc mockMvc;@MockBeanprivate UserInfoService mockUserInfoService;@Testpublic void testGetUserInfoList() throws Exception {// Setup// Configure UserInfoService.list(...).final UserInfo userInfo = new UserInfo();userInfo.setId(0);userInfo.setUserName("MyBatis Log Free");userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());final List<UserInfo> userInfos = Arrays.asList(userInfo);when(mockUserInfoService.list()).thenReturn(userInfos);// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
//        assertThat(response.getContentAsString()).isEqualTo("expectedResponse");}@Testpublic void testGetUserInfoList_UserInfoServiceReturnsNoItems() throws Exception {// Setupwhen(mockUserInfoService.list()).thenReturn(Collections.emptyList());// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());assertThat(response.getContentAsString()).isEqualTo("[]");}@Testpublic void testSaveUser() throws Exception {// Setupwhen(mockUserInfoService.save(new UserInfo())).thenReturn(false);// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/save/user").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());assertThat(response.getContentAsString()).isEqualTo("expectedResponse");verify(mockUserInfoService).save(new UserInfo());}@Testpublic void testGetUserInfoListIds() throws Exception {// Setup// Configure UserInfoService.queryUserInfoList(...).final UserInfo userInfo = new UserInfo();userInfo.setId(0);userInfo.setUserName("MyBatis Log Free");userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());final List<UserInfo> userInfos = Arrays.asList(userInfo);when(mockUserInfoService.queryUserInfoList("2022-09-05 15:11:21", Arrays.asList(0))).thenReturn(userInfos);// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/ids").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());assertThat(response.getContentAsString()).isEqualTo("expectedResponse");}@Testpublic void testGetUserInfoListIds_UserInfoServiceReturnsNoItems() throws Exception {// Setupwhen(mockUserInfoService.queryUserInfoList("2022-09-05 15:11:21", Arrays.asList(0))).thenReturn(Collections.emptyList());// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/ids").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());assertThat(response.getContentAsString()).isEqualTo("[]");}@Testpublic void testGetUserInfoListLike() throws Exception {// Setup// Configure UserInfoService.queryListByUserName(...).final UserInfo userInfo = new UserInfo();userInfo.setId(0);userInfo.setUserName("MyBatis Log Free");userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());final List<UserInfo> userInfos = Arrays.asList(userInfo);when(mockUserInfoService.queryListByUserName("A")).thenReturn(userInfos);// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/like").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());assertThat(response.getContentAsString()).isEqualTo("expectedResponse");}@Testpublic void testGetUserInfoListLike_UserInfoServiceReturnsNoItems() throws Exception {// Setupwhen(mockUserInfoService.queryListByUserName("A")).thenReturn(Collections.emptyList());// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/like").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());assertThat(response.getContentAsString()).isEqualTo("[]");}@Testpublic void testSaveUserInfo() throws Exception {// Setup// Run the testfinal MockHttpServletResponse response = mockMvc.perform(get("/boot/save/userinfo").accept(MediaType.APPLICATION_JSON)).andReturn().getResponse();// Verify the resultsassertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());assertThat(response.getContentAsString()).isEqualTo("expectedResponse");verify(mockUserInfoService).saveUser(new UserInfo());}
}

@Mock用于模拟不属于 Spring 上下文的对象，而@MockBean用于模拟属于 Spring Boot 应用程序中的 Spring 上下文的对象。@MockBean提供与 Spring Boot 测试框架的无缝集成，并允许在测试期间用模拟对象轻松替换实际 bean

Mockito提供了多种参数匹配器（Matchers）用于更灵活的验证和配置行为：

import static org.mockito.ArgumentMatchers.*;
when(mockRepository.findById(anyInt())).thenReturn(Optional.of(user));
verify(mockRepository).findById(eq(1));

常见的匹配器包括：

　　·any()：匹配任何参数

　　· anyInt()：匹配任何整数参数

　　· eq(value)：匹配特定值

　　· isNull()：匹配null值

　　· notNull()：匹配非null值

Mock异常

Mockito.when(userMapper.getUserById(Mockito.anyInt())).thenThrow(new RuntimeException("运行时错误"));Assertions.assertThrowsExactly(RuntimeException.class, () -> userMapper.getUserById(1));// 对于没有返回值的方法，不能使用thenThrow()来抛出异常，可以使用doThrow()来抛出异常。
Mockito.doThrow(new RuntimeException("运行时错误")).when(userMapper).getUserById(1);
Assertions.assertThrowsExactly(RuntimeException.class, () -> userMapper.getUserById(1));

@MockBean 是 Spring Boot 提供的注解，它用于在测试中创建一个 mock 对象，并将其注入到 Spring 上下文中，替换掉原来的真实 Bean。需要使用SpringJUnit4ClassRunner.class之类的注解

@Mock: 用于代替Mockito.mock创建mock对象,创建一个Mock实例，需要基于JUnit5环境。@InjectMocks: 创建一个实例，其余用@Mock（或@Spy）注解创建的mock将被注入到用该实例中。

你要测试哪个类（如TemplateUserServiceImpl ），那么就用 @InjectMocks注解；被测试的类中通过 @Autowired注解注入了几个，那么测试类里面就用@Mock注解创建几个实例！

原始代码：

@Service
public class TemplateUserServiceImpl implements TemplateUserService {@Autowiredprivate NamedParameterJdbcTemplate jdbcTemplate;@Transactional@Overridepublic void saveUser() {UserInfo userInfo = new UserInfo();userInfo.setId(7);userInfo.setUserName("Boot");Date startTime = new Date();Date endTime = new Date();userInfo.setCreateTime(startTime);userInfo.setUpdateTime(endTime);// JdbcTemplate的写入datetime,使用in方式
//        String sql="insert into user_info(user_name,create_time,update_time) values(:user_name,:create_time,:update_time)";String sql="insert into user_info(user_name,create_time,update_time) values(:userName,:createTime,:updateTime)";SqlParameterSource sqlParameterSource=new BeanPropertySqlParameterSource(userInfo);
//        HashMap paramMap = new HashMap<>();
//        paramMap.put("user_name",userInfo.getUserName());
//        paramMap.put("create_time",userInfo.getCreateTime());
//        paramMap.put("update_time",userInfo.getUpdateTime());
//        jdbcTemplate.update(sql,paramMap);jdbcTemplate.update(sql,sqlParameterSource);}
}

对应单元测试代码：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;@RunWith(MockitoJUnitRunner.class)
public class TemplateUserServiceImplTest {@Mockprivate NamedParameterJdbcTemplate mockJdbcTemplate;@InjectMocksprivate TemplateUserServiceImpl templateUserServiceImplUnderTest;@Testpublic void testSaveUser() {// Setup// Run the testtemplateUserServiceImplUnderTest.saveUser();// Verify the resultsverify(mockJdbcTemplate).update(eq("insert into user_info(user_name,create_time,update_time) values(:userName,:createTime,:updateTime)"),any(SqlParameterSource.class));}@Testpublic void testSaveUser_NamedParameterJdbcTemplateThrowsDataAccessException() {// Setupwhen(mockJdbcTemplate.update(eq("insert into user_info(user_name,create_time,update_time) values(:userName,:createTime,:updateTime)"),any(SqlParameterSource.class))).thenThrow(DataAccessException.class);// Run the testassertThatThrownBy(() -> templateUserServiceImplUnderTest.saveUser()).isInstanceOf(DataAccessException.class);}
}